US Helicopters Kill 28 Pakistani Troops on Afghan Border

US attack helicopters killed 28 Pakistani troops manning a border outpost along the Afghan border, according to Pakistani military officials. Pakistan has retaliated by closing the vital Khyber Pass to NATO supply trucks.

The US helicopters struck an outpost in the Baizai area of the Taliban-controlled tribal agency of Mohmand, Pakistani officials said. The attack took place at the Salala check post, which is just over a mile from the border with Afghanistan.

"NATO helicopters carried out an unprovoked and indiscriminate firing on a Pakistani check post in Mohmand agency, casualties have been reported and details are awaited," a Pakistani military spokesman told Reuters. Up to 28 Pakistan troops, including two officers, are said to have been killed and 11 more have been wounded, Dawn reported.

The International Security Assistance Force (ISAF) said it was aware of reports of US helicopters engaging Pakistani forces and that it was investigating.

The reported attack took place just across the border from Afghanistan's eastern province of Kunar, a known stronghold of the Taliban, al Qaeda, and allied terror groups. Afghan troops are currently conducting an operation in neighboring Nuristan province, another Taliban and al Qaeda bastion. US forces have mostly withdrawn from Kunar and Nuristan, and are relying on airstrikes and sweeps to keep the Taliban at bay.

The reason for the US attack in Mohmand is unclear. The border is unmarked and the terrain is rugged. Pakistan and Afghanistan also dispute the international border, which is known as the Durand Line.

The US has also conducted several cross-border attacks while in "hot pursuit" of Taliban forces. ISAF has maintained that it has the right to pursue retreating Taliban forces "after following the proper rules of engagement under inherent right of self defense." [See LWJ report, Pakistan closes NATO supply route after latest US cross-border attack]

The US has pursued Taliban fighters across the border multiple times in the past. Two of the most high-profile incidents occurred in 2008, and three others took place in 2010. The first took was in June 2008, when US troops pursued a Taliban force from Kunar into Mohmand, and killed 11 fighters. The Pakistani government claimed that the US killed Frontier Corps troops, but the US released video of the incident showing the Taliban being targeted as they fled from Kunar into Mohmand. Pakistan's paramilitary Frontier Corps is known to support the Taliban in Afghanistan.

The second incident took place in Khyber in November 2008, when US forces launched rocket attacks and ground strikes into the Tirah Valley, a known haven for al Qaeda, the Taliban, and the Lashkar-e-Islam. Seven people were reported killed and three were wounded in the strikes.

The last three such incidents took place in the fall of 2010, when US helicopters attacked Haqqani Network fighters crossing back into the Pakistani tribal agencies of North Waziristan and Kurram after the terror group attacked US bases in Khost and Paktia provinces. More than 50 Haqqani Network fighters were reported killed in the Kurram attacks. Pakistan claimed two Frontier Corps troops were killed.

The US incursions into Pakistan have infuriated the country's military establishment. The Pakistani government closed the Khyber Pass, one of the two key crossing routes for NATO supplies, for 10 days after the attacks in 2010. During that time, more than 200 NATO fuel tankers and supply trucks and containers were savaged in major attacks against convoys and rest stops in Baluchistan and Khyber-Paktunkwha provinces, as well as just outside the cities of Islamabad and Rawalpindi.

The border crossing was reopened on Oct. 9 after top US generals, including ISAF commander General David Petraeus, and US officials apologized for the cross-border strikes.

The US also launches covert airstrikes using unmanned Predators and Reapers against al Qaeda and the Taliban in Pakistan's tribal areas.

In addition, the US carried out a unilateral special operations raid in May deep into Pakistani territory and killed Osama bin Laden at his hideout in Abbottabad, which was not far from Pakistan's top military academy.

Note: this article has been updated to reflect new casualty figures and Pakistan's closing of the Khyber Pass.